Ascorbic acid, hindered phenols, phenidone, and 5-hydroxy-2-hydroxymethyl-4-pyrone (known as Kojic acid), have been used with silver films as developers (L. F. A. Mason, Photographic Processing Chemistry, The Focal Press, London, 1966 (pages 15 and 17)). These materials have also been used with leuco dyes in transparency imaging systems to stabilize the leuco dyes against oxidation and premature reaction (commonly assigned copending U.S. Ser. No. 199,444, filed Oct. 22, 1980). Although these materials are useful to stabilize less sensitive leuco dyes which require higher temperatures and longer exposure times to image, they have not been found useful with the more sensitive, faster imaging, leuco dyes, particularly, indolyl substituted triarylmethane dyes, styryl dyes, N-acyl oxazine dyes, N-acyl thiazine dyes, cyanine dyes, N-acyl diazine dyes and xanthene dyes.